Pre-coated particles for chemical mechanical polishing

ABSTRACT

The present invention relates to the manufacture and use of novel pre-coated abrasive particles and particle slurries for the chemical mechanical polishing (CMP) of semiconductor wafers, thin films, inter-layer dielectric, metals, and other components during integrated circuit, flat panel display, or MEMS manufacturing. For example, polishing slurry abrasive particles can be pre-coated with additives, such as, inhibitors and/or surfactants during manufacture of the abrasive particles or slurry. The additive&#39;s opportunity to react directly with the abrasive particles early in the particle manufacturing process provides a slurry having a more stable, selectable, and predictable ratio of abrasive particles pre-coated with a more stable, selectable, and predictable amount and type of additives.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 10/307,274 filed Nov. 27, 2002 entitled, “Pre-coated Particlesfor Chemical Mechanical Polishing.”

BACKGROUND OF THE INVENTION

1. Field of the Invention

Polishing slurries and particles.

2. Description of Related Art

Typical integrated circuit (“IC”) manufacturing techniques involve thefabrication of multiple IC chips on a single semiconductor or substratewafer. In turn, each chip may be made up of millions of electronicdevices (e.g., transistors, resistors, capacitors) formed in the siliconsubstrate. Generally, the function of each device is dictated by thechemical makeup and geography of the substances it contains. Thus,during fabrication, the formation of these devices involves a sequenceof operations aimed at adding, shaping and removing various chipsubstances by having these substances grown, deposited, removed,chemically altered, and polished in selected areas on the wafer. Forinstance, the surface of a wafer may be polished to assure that thedevice surfaces are flat or to remove excess material from the surfaceof the devices prior to the next manufacturing operation. Polishing ofwafer surfaces is often referred to as “planarization”.

One technique for planarizing the top surface of semiconductor wafers isto polish the surface using a polishing “slurry” having abrasiveparticles mixed in a solution or suspension agent in achemical-mechanical polishing (CMP) process. CMP processes and slurriesare used for the polishing of semiconductor wafers, inter-layerdielectric layers, metal layers or lines, thin films, and othercomponents during integrated circuit manufacturing. For instance, CMP isoften used for planarizing tungsten interconnects, vias and contacts.CMP slurries typically include abrasive particles such as alumina;silica or ceria, such as oxides of aluminum, silicon or cerium; a ferricsalt oxidizer such as ferric nitrate; a suspension agent such aspropylene glycol; and deionized water. In CMP, the abrasive particlesprovide friction while oxidants and/or etchants can be used to cause achemical reaction at the wafer surface. Slurry additives can also beused to enhance the removal rate, uniformity, selectivity, etc.

In a typical chemical mechanical polishing process, the substrate orwafer is placed face-down on a polishing pad which is attached to arotatable table. In this way, the material to be polished (e.g., atungsten or copper film) is placed in direct contact with pad. A carriercan be used to hold the wafer, as well as to apply a downward pressureagainst the backside of substrate. During the polishing process, pad andtable are rotated while a downward force is placed on substrate bycarrier. The abrasive and chemically reactive solution or “slurry” isintroduced or deposited onto the pad during polishing. The slurryinitiates the polishing process by chemically reacting with the material(e.g., a film) being polished. The polishing process is facilitated bythe rotational movement of pad relative to wafer as slurry is providedto the wafer/pad interface. Polishing is continued in this manner untila desired amount of the material (e.g., all of the film on theinsulator) is removed.

Commercially available CMP equipment and slurries are available forplanarization of integrated circuits. Typically, a high-shearing typedispersion machine is used to produce the abrasive particles for a CMPslurry solution. However, current CMP slurries exhibit problems such asseparation within the slurry of abrasive and additive particles,displacement of additives due to a shortage of chemical reactionsbetween the abrasive and additive particles, and non-uniformdistribution of the abrasive and/or additive particles in the slurry.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram describing the manufacture of pre-coatedabrasive particles for use in a CMP slurry.

FIG. 2 is a cross-sectional illustration showing a shear mixer and apre-coated abrasive particle manufactured with additive coatings bymixing.

FIG. 3 is a cross-sectional illustration showing a fuming chamber andpre-coated abrasive particles manufacture with additive coatings byfuming.

FIG. 4 is a cross-sectional illustration showing pre-coated abrasiveparticles manufactured with surfactant and/or inhibitor coatings.

FIG. 5 is a cross-sectional illustration showing a semiconductor filmbeing polished by pre-coated abrasive particles manufactured withadditive coatings.

FIG. 6 is a cross-sectional illustration showing a pre-coated abrasiveparticle manufactured with an additive precursor coating which is inturn coated with an additive.

FIG. 7 is a cross-sectional illustration showing a pre-coated abrasiveparticle manufactured with a precursor particle covalently bonded to itwhich is in turn covalently bonded to an additive particle.

DETAILED DESCRIPTION

Methods, apparatus, and systems related to the manufacture and use ofabrasive particles and abrasive particle slurries for the chemicalmechanical polishing (CMP) of components during manufacture of circuitdevices is described. According to embodiments, polishing slurryabrasive particles are pre-coated with additives, such as, inhibitorsand/or surfactants during manufacture of the abrasive particles orslurry. The particles are described as “pre-coated” in one sense,because the additives are introduced (e.g., added, bonded, etc.) to theabrasive particles prior to the introduction of a chemical solution toform the chemical (solution) mechanical (pre-coated particle) polishingslurry. For example, a selected portion of a group of abrasive particlescan be manufactured having a selection of additive inhibitor and/orsurfactant particles chemically bonded to them for polishingsemiconductor wafers, thin films, inter-layer dielectric, metals, andother circuit device components. In addition to planarization of wafersin the IC fabrication, planarization techniques (e.g., CMP) using suchpre-coated particle slurries can be used in hard disk and CDmanufacturing, optical materials and Micro Electro Mechanical Systems(MEMS) manufacturing. These pre-coated abrasive particles are then mixedwith a solution to form a CMP slurry.

In the following description, the terms “pre-coated particles” or“pre-coating particles” describe a quantity of abrasive or otherparticles that have additives such as inhibitor and/or surfactantchemically bonded to them during manufacture. For example, pre-coatedparticles describes abrasive particles (alone or mixed in a slurry) thathave inhibitor and/or surfactant particles chemically bonded to thembefore, during, or after the shear mixing. In addition, herein, the term“slurry” refers to a composition used for chemical-mechanical polishing(CMP) that generally includes a mixture of a solution that may or maynot also contain an oxidizing agent, and a desired amount and type ofabrasive particles that may or may not have interactions or attractionswith additives. Moreover, the terms “manufacture”, “production”,“fabrication”, “make”, “construct”, “form”, “generate”, and “create” areused to describe the various operations or events (whether necessary ornot) included in creating abrasive particles or slurries for polishmaterial using CMP or other appropriate methods. Furthermore, the terms“mix”, “combine”, “add”, and “introduce” are used herein to describe theadding together of two substances, such as abrasive particles andadditives

Embodiments contemplate various interactions or attractions betweenabrasive particles and additives such as bonding (covalently, ionically,etc.), force interaction or attraction (e.g., Van der Waals force,etc.), and abrasives that adhere to or are fused with additives. Forinstance, an abrasive particle “pre-coated” with additive can explain asituation where the abrasive particle and additive are chemically bonded(e.g., by covalent electron sharing), or attracted by a Van der Waalsforce.

According to embodiments, a CMP slurry may include the pre-coatedabrasives particles added to a solution that may include, for example, abase, an acid, a complexing agent and/or an aqueous surfactant such thatimproves the colloidal behavior of the abrasive particles in deionizedwater, and inhibits the growth and/or coalescence of the preexistingparticles. Thus, for instance a complexing agent can be a commerciallyavailable aqueous mixture of 1) glycols such as ethylene glycol,propylene glycol and glycerol; 2) polyethers such as polyethyleneglycol; 3) aliphatic polyethers; and/or 4) akoxylated alkyphenols. Inaddition, various other appropriate substances may be used for solutionas provided by the current state of the art.

Suitable abrasive particles include particles such as (but not limitedto) silica or silicon dioxide (SiO₂), ceria (CeO), alumina (Al₂O₃), ortitanium oxide (Ti₂O₃), diamond (colloidal like), silicon carbide (SiC),and silicon nitride (Si₃ N₄). In addition, various other appropriatesubstances may be used for abrasives as provided by the current state ofthe art. These abrasives can be used alone or as mixtures.

Moreover, embodiments provide for pre-coating particles with additives(e.g., generally, an “additive” is any substance that can be added toabrasive particles and water that does not cause the slurry to becomeunusable) such as surfactants, inhibitors, liquid polymers, oxidants,precursors to the aforementioned, and/or some ratio of all of theaforementioned. For instance, surfactants that wet the wafer surface orsurface to be polished, and/or particle surface and change a hydrophilicor hydrophobic character of the surface, modify selectivity, and/ormodify viscosity may be used. Also, additives may include inhibitorssuch as, but not limited to, TTA, benzotriazole (BTA), and variousappropriate metal corrosion inhibitors. Likewise, additives may includeoxidizing agents including, but not limited to, potassium ferricyanide,potassium dichromate, potassium iodate, hydrogen peroxide, iodinate,potassium bromate, and vanadium trioxide. Similarly, additives maycomprise precursors capable of interacting with or attracting one ormore additives. Various other appropriate substances may be used foradditives as provided by the current state of the art.

As a result of embodiments, due to the additives opportunity to reactdirectly with the abrasive particles early in the particle manufacturingprocess, the probability for the additives such as an inhibitor,surfactant, liquid polymer, and/or some ratio of any or all of thosecomponents to coat or adhere to the abrasive particle is increased.Depending on the ratio of the particle concentration to additives it ispossible to thoroughly coat some selected or predictable percentage ofthe abrasive particles (including coating all abrasive particles). Forexample, two, three or more different types of coated particles can beused within one slurry. Since a coated particle will not usually berecoated, it is possible to use a coated and a non-coated particle in asingle slurry. Therefore, one single slurry can include a particlecoated with additives and another particle that is not coated at all.Also, the methodology will potentially decrease energy needed in themixing and blending stage of the final product due to slow equilibratingadditives and particles. Furthermore, the amount of contact of inhibitorwith the polishing surface within the reach of abrasive particles isimproved.

Moreover, according to embodiments, pre-coating the abrasive particlesby introducing an inhibitor, such as BTA, or a surfactant, or both intoa CMP slurry, will change the surface morphology and zeta potential ofthe particles. The result will be a decrease in the potential forparticle agglomeration, and a substantial decrease or elimination in theuse of inhibitors or surfactants in the slurry itself.

Thus, once the particle is pre-coated the use of particle dispersion ina slurry solution may also be minimized. This methodology will alsoprovide a means to create a slurry with different particles that willbehave and function differently depending on the process application andprocess stage (e.g., a slurry with a certain effectiveness during oneCMP process and having another effectiveness during a subsequent CMPprocess).

Pre-Coating Methods During Abrasive Particle Manufacture

According to embodiments, coating of the abrasive particles withadditives can be done before, during, or after (e.g., one particlemanufacturing operation after) the shear-mixing or fuming operation ofabrasive particle manufacturing. Fuming is a process used inmanufacturing of the particle itself, that generally takes place beforeshear-mixing. Additionally, coating can be performed during any numberof operations including before, during and after shear-mixing, solutionmixing, and/or particle manufacturing.

For instance, FIG. 1 is a block diagram describing the manufacture ofpre-coated abrasive particles for use in a CMP slurry. As shown in FIG.1, abrasive particles are formed by fuming (heating) in heat pressurereaction (block 101), and then cooled to create suitable sized particlesfor slurry (block 102). For example, abrasive metal oxides can be formedby oxidation and flame hydrolysis of metal chloride vapor having metalsthat include Si, Ti, Al, Fe, and/or Zr. FIG. 1 also shows solutionformation nucleation of particles in saturated solutions (block 103),followed by solution particle growth (block 104). Thus, particleformation by hot fuming and/or solution formation may be used in anembodiment of the invention, although particle formation by variousother appropriate methods are also within the contemplation and scope ofthe invention. Afterwards, the created abrasive particles may bepre-coated with additives in at least one of the following four ways.First, the created abrasive particles may be pre-coated with additivesby introducing one or more additives collectively or in series to thecreated abrasive particles (block 106) prior to shear mixing of thecombination. Then, the combination of additives and created abrasiveparticles can be shear mixed (block 107) for separation and to formabrasive particles pre-coated with additives (e.g., to form uniformdistribution of the pre-coated abrasive particles). As such, embodimentscontemplate introduction of the additives to the created abrasiveparticles seconds, minutes, days, or longer periods prior to shearmixing of the combination in order to provide a desired chemistry.Second, the created abrasive particles may be pre-coated with additivesby introducing one or more additives collectively or in series to thecreated abrasive particles during shear mixing of the combination (block108) for separation and to form abrasive particles pre-coated withadditives (e.g., to form uniform distribution of the coated abrasiveparticles). Third, the created abrasive particles may be pre-coated withadditives by introducing one or more additives collectively or in seriesto the created abrasive particles (block 110) after shear mixing of thecreated abrasive particles. Here, the created abrasive particles can beshear mixed (block 109) for separation and to form uniform distributionof the pre-coated abrasive particles. Then, the shear mixed abrasiveparticles can be introduced to additives (block 110) to form abrasiveparticles pre-coated with additives. Embodiments also contemplateintroducing the created abrasive particles with additives as describedabove, without shear mixing of the particles. Fourth, the additive(s) isintroduced to the abrasive during the shear-mixing stage (block 111) andonce coated the abrasives are then added, moved, transferred to anothervessel for additional shear-mixing including addition/introduction ofsame abrasives with different surface morphology that are not coated(block 112) with additives or an addition/introduction of differentabrasives to the pre-coated abrasives. For instance, after the additivesand abrasives are combined, a second shear mixing operation can be usedto select out certain ones of abrasive particles with and/or withoutadditive coatings to provide a selected ratio of such particles.

Additionally, filtering, combining with a solution, and/or remixing thepre-coated abrasive particles with another slurry 113 can be used toprovide a slurry having a selected ratio of additive coated abrasiveparticles as compared to the abrasive particles not coated by additives.A final version of pre-coated abrasive particle slurry can then bemanufactured for storage, transport, and/or at point of use polishing114. For instance, a slurry can be created having a ratio of pre-coatedabrasive particles such that the slurry reaches a stable, selectable,and/or predictable enough particle state to be stored 116, transported118, and/or used locally 120, say 30 minutes after creation of theslurry, for chemical-mechanical polishing.

The shear-mixing stage of abrasive particle manufacturing is typicallyused to de-agglomerate the abrasive particles (e.g., silica, ceria,and/or alumina) from each other and to provide particle dispersion aswell as pH adjustment (e.g., block 106). According to embodiments, thisoperation can be used to introduce additives to the abrasive particles.For example, FIG. 2 is a cross-sectional illustration showing a shearmixer and pre-coated abrasive particle manufactured with additivecoatings by mixing.

As shown in FIG. 2, shear mixer 210 is used to precoat abrasive particle200 with additives. In this example, the abrasive particles arepre-coated before they are added to a chemical solution to form a CMPslurry. Embodiments also consider pre-coated abrasive particles thathave inhibitor and/or surfactant bonded to them before, during, or aftershear mixing, fuming, filtering, selection, collection, sorting,segregation, and/or isolation. As shown in FIG. 2, pre-coated particle210 is comprised of abrasive center portion 120 coated or surrounded byadditive 230. This coating or bonding includes various interactions orattractions between abrasive particles and additives such as covalentand ionic bonding, as well as force attractions such as Van der Waalsforce. It should be pointed out that both full coverage, as well aspartial coverage of an abrasive core by additives are plausibleaccording to the invention. Using this methodology or system, thesurface morphology of abrasive particles 220, such as silica, ceria,alumina, or titanium dioxide, can be changed due to the surface of theabrasive particle being coated by additive 230. As such, additivecoating 230 (e.g., surfactant, inhibitor, liquid polymers, oxidizer,precursor, and/or some ratio of all) can change the abrasive particle'sinteraction with its surrounding environment. For instance, inhibitorand/or surfactant can be added to the shear-mix slurry to createpre-coated particles to inhibit corrosion, and surface defectivity,especially in case of metal CMP processes such as copper.

Also, according to embodiments, a fuming process can be usedindependently or in conjunction with shear mixing, as well as variousother appropriate mixing operations and/or solutions to form pre-coatedabrasive particles, during abrasive particle and/or pre-coated abrasiveparticle production. FIG. 3 is a cross-sectional illustration showing afuming chamber and pre-coated abrasive particles manufactured withadditive coatings by fuming. Abrasive particles 370 formed then passinto combining region 320 (e.g., spray region) where they are combinedwith one or more additives 322 collectively or in series to formpre-coated abrasive particles 372 made up of ones of abrasive particlescoated with one or more types of additive 322 (e.g., one or moreinhibitor(s) and/or surfactant(s) added collectively, or in series, inany order). The pre-coated particles are then cooled in cooling region330 (e.g., to create pre-coated particles of a particular size). Thecooled pre-coated abrasive particles 374 are then collected incollection chamber 340 for use in the next slurry manufacturingoperation (e.g., mixed with a solution to form slurry).

Correspondingly, embodiments may incorporate mixture in a solution ofadditives and abrasives (e.g., mixture without a shear mixer)independently or in conjunction with shear mixing and/or fuming, as wellas other appropriate operations, during abrasive and/or pre-coatedabrasive particle production. Various other appropriate coated particlemixing and slurry fabrication techniques for selecting a ratio of coatedabrasives, non-coated abrasives, solution, oxidizer, inhibitor,surfactant, precursor, and/or other additives may be performed duringany number of manufacturing operations including before, during andafter shear-mixing, solution mixing, and/or fuming operations.

Pre-Coating Compositional Mixtures

According to embodiments, depending on the ratio of the particleconcentration to various additive concentrations in a mix, it ispossible to thoroughly coat some selected or predictable percentage orratio of the abrasive particles (including coating all abrasiveparticles) with a selection of one or more additives. Particularly,abrasive particles 220 may be pre-coated with additives 230 such as aninhibitor, surfactant, oxidizer, pH buffer (or pH stabilizing agent),precursor, and/or liquid polymer, or some combination or ratio of any orall the above. For instance, FIG. 4 is a cross-sectional illustrationshowing pre-coated abrasive particles 410 manufactured with surfactantand/or inhibitor coatings. As a result, an abrasive particle may bemanufactured with only one additive coating such as pre-coated particle410 or pre-coated particle 420. As shown in FIG. 4, pre-coated particle410 comprises abrasive particle 412 pre-coated with inhibitor 414.Similarly, pre-coated particle 420 is comprised of abrasive centerportion 422 pre-coated or surrounded with surfactant 424.

Moreover, an abrasive particle may be pre-coated with any combination,order, or number of surfactant, inhibitor, oxidizer, pH buffer,precursor, and/or liquid polymers. Thus, particles may be pre-coatedwith two different additives or with various types of surfactant,inhibitor (e.g., such as a buffer adjusting pH component), and liquidpolymers. As shown in FIG. 4, pre-coated particle 440 comprises anabrasive particle 442 pre-coated with an inhibitor 444 and withsurfactant 446. Similarly, pre-coated particle 430 is comprised ofabrasive center portion 432 pre-coated or surrounded with two types ofsurfactant 434 & 438, and two types of inhibitor 436 & 439. Likewise,pre-coated particle 450 comprises an abrasive particle 452 pre-coatedwith inhibitor 454 and with a polymer coating 456 (e.g., bonded from aliquid polymer solution).

Likewise, the abrasive particles described above may be pre-coated witha selected amount of one or any number of surfactant, inhibitor, and/orliquid polymer additives. Thus, a selection of pre-coated abrasiveparticles may be manufactured having particles that are partially orfully pre-coated with one single, or two or more different additives.For instance, pre-coated particle 440 comprises abrasive particle 442pre-coated half with inhibitor 444, and half with surfactant 446.Similarly, pre-coated particle 430 comprises abrasive particle 432pre-coated one quarter with one type of inhibitor 436, one quarter witha second type of inhibitor 439, one quarter with one type of surfactant434, and one quarter with a second type of surfactant 438. In forming aslurry, these selections can now be mixed to form a desired slurrycomprising a ratio of completely and partially pre-coated abrasiveparticles. The selections can also be mixed to form a slurry having amixture of completely and partially pre-coated abrasive particles, aswell as non-pre-coated abrasive particles.

Moreover, according to embodiments during manufacture or slurryformation various factors can be used to adjust the ratio of: 1)pre-coated abrasive particles (including the ratio of coatings havingdifferent percentages of various additive compositions, such as partsurfactant part inhibitor, all surfactant, and/or all inhibitor), 2)non-coated abrasive particles, and 3) non-interacting additiveparticles. For instance, such factors include but are not limited to: 1)the number and types of compositions that make up the additives and thechemical comparison of the additives to the abrasive particles; 2) theamount of additives introduced to the abrasive particles; 3) a timeperiod of the introduction of the additives to the abrasive particles;4) a temperature of the abrasive particles and additives during theintroduction of the additives; and 5) an atmospheric pressure applied tothe abrasive particles and to the additive during the introduction ofthe additives to the abrasive particles. Various other appropriatefactors may be used to adjust the amount, ratio, and types of additivesmixed with abrasives as is provided by the current state of the art.

Adjusting factors such as those described above to mix additives andabrasive particles during abrasive particle manufacture, allows forknown, stable, selectable, and predictable amounts or ratios ofpre-coated abrasive particles as compared to abrasive particles withoutadditives to be formed. Hence, for instance, the mixture of coated andun-coated particles can be controlled by modifying the type and percentof additive introduced for bonding with the abrasive particles in aparticle shear-mixing process. For example: $\begin{matrix}\left. {\frac{100\quad{ml}}{10\quad\min}\quad{additive}\quad A}\Rightarrow{15\quad\%\quad{of}\quad{abrasives}\quad{covered}} \right. & (a) \\\left. {\frac{100\quad{ml}}{10\quad\min}\quad{additive}\quad B}\Rightarrow{25\quad\%\quad{of}\quad{abrasives}\quad{covered}} \right. & (b)\end{matrix}$

In Equation a), 100 milliliters of additive “A” (e.g., an additive asdescribed herein that is different than additives “B”, “C”, or “D”) isintroduced to a selected plurality of abrasive particles for 10 minutes.The result is a selected ratio where 15% of the abrasive particles havebecome pre-coated abrasive particles (coated with additive “A”), and theother 85% of the abrasive particles are non-coated. In a like manner, inEquation b), 100 milliliters of additive “B” (e.g., an additive asdescribed herein that is different than additives “A”, “C”, or “D”) isintroduced to a selected plurality of abrasive particles for 10 minutes.The result is a selected ratio where 25% of the abrasive particles havebecome pre-coated abrasive particles (coated with additive “B”), and theother 75% of the abrasive particles are non-coated. Moreover, theseselections can now be mixed to form a desired slurry comprising a ratioof combined abrasive particles pre-coated with additive “A”, abrasiveparticles pre-coated with additive “B”, and non-pre-coated abrasiveparticles for instance, mixing equal portions of results from Equationa) with results from Equation b) will provide a selection having a ratiowhere 7.5% of the abrasive particles have become pre-coated abrasiveparticles (coated with additive “A”), 13.5% of the abrasive particleshave become pre-coated abrasive particles (coated with additive “B”),and the other 79% of the abrasive particles are non-coated. Indeed,pre-coated particles can also be gathered from the selections and mixedto form a slurry of abrasive particles pre-coated with additive “A” andabrasive particles pre-coated with additive “B” that does not includenon-pre-coated abrasive particles.

The ensuing example shows two types of additives being simultaneouslymixed with abrasive particles: $\begin{matrix}{\left\lbrack {\frac{100\quad{ml}}{10\quad\min}\quad{additive}\quad C} \right\rbrack\quad{\left. {{and}\quad\left\lbrack {\frac{100\quad{ml}}{10\quad\min}\quad{additive}\quad D} \right\rbrack}\Rightarrow{25\quad\%\quad C} \right.,{10\%\quad D},{\&\quad 5\quad\%{CD}}}} & (c)\end{matrix}$

In Equation c), 100 milliliters of additive “C” (e.g., an additive asdescribed herein that is different than additives “A”, “B”, or “D”) and100 milliliters of additive “D” are introduced to a selected pluralityof abrasive particles for 10 minutes. The result is a selected ratiocomprising 25% pre-coated abrasive particles coated with additives “C”,10% pre-coated abrasive particles coated with additive “D” (e.g., anadditive as described herein that is different than additives “A”, “B”,or “C”), 5% pre-coated abrasive particles coated with additive “C” and“D”, and the other 60% of the abrasive particles are non-coated. Again,portions, selections, or gatherings of these particles can be combinedwith those resulting from Equation a) and/or Equation b) as describedabove.

Likewise, the type and mixture of coated and un-coated particles can becontrolled by modifying the type and time period of the introduction ofthe additives to the plurality of abrasive particles during pre-coatingin a particular shear-mixing process. The following is an example whereboth the amount and types of additives introduced and a time period ofthe introduction of the additives to the abrasive particles aremodified: $\begin{matrix}{\left\lbrack {\frac{150\quad{ml}}{20\quad\min}\quad{additive}\quad C} \right\rbrack\quad{\left. {{and}\quad\left\lbrack {\frac{100\quad{ml}}{10\quad\min}\quad{additive}\quad D} \right\rbrack}\Rightarrow{50\quad\%\quad C} \right.,{10\%\quad D},{\&\quad 10\quad\%{CD}}}} & (d)\end{matrix}$

In Equation d), 150 milliliters of additive “C” is introduced for 20minutes and 100 milliliters of additive “D” is introduced for 10 minutesto a selected plurality of abrasive particles. The result is a selectedratio comprising 50% pre-coated abrasive particles coated with additive“C”, 10% pre-coated abrasive particles coated with additive “D”, 10%pre-coated abrasive particles coated with additive “C” and “D”, and theother 30% of the abrasive particles are non-coated. Again, portions,selections, or gatherings of these particles can be combined with thoseresulting from Equations a), b) and/or c) as described above.

Moreover, according to embodiments, a solution used to create aselection of pre-coated particles in one mixing stage (e.g., solutionand results of Equation c)) can then be added to (e.g., add solution ofEquation a)) to create another result in a subsequent mixing stage. Inthis manner, two resulting ratios of pre-coated particles can beefficiently produced by adding additive to a single solution. Forinstance, taking the solution of Equation c) and adding the additives ofEquation a) gives: $\begin{matrix}\begin{matrix}{\left. \left\lbrack {\frac{100\quad{ml}}{10\quad\min}\quad{additive}\quad A} \right\rbrack\quad{{and}\quad\left\lbrack {\frac{100\quad{ml}}{10\quad\min}\quad{additive}\quad C} \right\rbrack}\quad{{and}\left\lbrack {\frac{100\quad{ml}}{10\quad\min}\quad{additive}\quad D} \right\rbrack}\Rightarrow{9\quad\%\quad A} \right.,{19\%\quad D},{\&\quad 4\quad\%\quad{CD}}} & \quad\end{matrix} & (e)\end{matrix}$

In Equation e), 100 milliliters of additive “A”, 100 milliliters ofadditive “C”, and 100 milliliters of additive “D” are introduced for 10minutes to a selected plurality of abrasive particles. The result is aselected ratio comprising 9% pre-coated abrasive particles coated withadditive “A”, 22% pre-coated abrasive particles coated with additive“C”, 9% pre-coated abrasive particles coated with additive “D”, 4%pre-coated abrasive particles coated with additive “C” and “D”, and theother 56% of the abrasive particles are non-coated. Again, portions,selections, or gatherings of these particles can be combined with thoseresulting from Equations a), b), c) and/or d) as described above. Also,in an embodiment of the invention, two different and distinct particlesizes may be used to create slurries that are pre-coated. For instance,abrasive A with a particular size which is statistically different insize and size distribution from abrasive B, can be coated with additivesand/or inhibitors. The additives and/or inhibitors coating abrasive Acan be similar or different from the additives and/or inhibitors thathave been used to coat abrasive B. Therefore, upon manufacturing theslurry, one can use these two differently coated abrasives withdifferent size (e.g., abrasives A and B) and coated with differentadditives to accomplish planarization selectivity or enhanceplanarization capability.

Consequently, according to embodiments, known types, amounts, and ratiosof pre-coated and non-coated abrasive particles can be selected andcollected from various mixing stages (e.g., as described above withrespect to initial and subsequent mixtures) to manufacture abrasiveparticles mixtures and slurries having a variety of predictable andselectable combinations and ratios of pre-coated and non-coated abrasiveparticles.

Moreover, embodiments contemplate using various mixing stages (e.g., asdescribed above with respect to initial and subsequent mixtures) toimprove population control of abrasives, coated-abrasive, and additivesin the slurry; decrease potential for particle agglomeration due to thechanged surface morphology and zeta potential of the pre-coated abrasiveparticles; reduce separation within slurry of abrasives, coatedabrasives, and additives; reduce displacement of additives due tochemical reactions possibly not taking place (e.g., between abrasivesand additives); reduce non-uniform distribution in the slurry (e.g.,between abrasives and abrasives, additives and additives, and abrasivesand additives); and decrease abrasive particle dispersion in the slurry.

In addition, according to embodiments, pre-coated abrasive particleslurries may be used during various processes and on various componentsduring the manufacture of circuit devices (e.g., semiconductorintegrated circuits) including, but not limited to, CMP of thin films,CMP of whole wafers, the formation of interconnections, and theplanarization of various layers. For instance, the pre-coated particlescan be used to polish other materials including but not limited totungsten silicide, copper and titanium nitride. In fact, the pre-coatedparticles can be applied to CMP processes used in areas other thansemiconductor processing such as flat panel display. Additionally,pre-coated particles can be used to improve processes where inhibitor orsurfactant or both are added to the slurry to prohibit corrosion, andsurface defectivity, such as metal CMP processes, and specificallycopper CMP where the requirements for the surface defectivity are verytight, consequently allowing, slurry manufacturing suppliers for suchCMP processes to manufacture and sell superior pre-coated abrasives andslurries.

As an example, FIG. 5 is a cross-sectional illustration showing asemiconductor film being polished by a CMP including pre-coated abrasiveparticles. FIG. 5 shows semiconductor film 510 being polished bypre-coated abrasives 520. According to FIG. 5, the substrate or wafer515 having film 510 is placed face-down on polishing pad 530 which isfixedly attached to rotatable table 535. In this way, thin film 510 maybe placed in direct contact with pad 530. Carrier 517 is used to apply adownward pressure against the backside of substrate 515. During thepolishing process, pad 530 and table 535 are rotated while a downwardforce “F” is placed on substrate 515 by carrier 517. The abrasive andchemically reactive “slurry” 520 can be deposited onto pad during orprior to polishing. Slurry 520 initiates the polishing process which maybegin, for example, when slurry 520 chemically reacts with film 510being polished. The polishing process is facilitated by the rotationalmovement of pad 530 relative to wafer 515 as slurry 520 is provided tothe wafer/pad interface. According to embodiments, pre-coated abrasiveparticle slurry may be added prior to or after the above describedpolishing contact or rotation begins.

As mentioned, pre-coating gives the additives opportunity to reactdirectly with the abrasive particles early in the particle manufacturingprocess. This opportunity increases the probability for the additives tocoat or adhere to the abrasive particles, which creates an increasedcontact of inhibitor with the polishing surface within reach of theabrasives, as well as a decrease in the potential for particleagglomeration. The effect, as shown in FIG. 5, is an improved chemicaland mechanical interaction of the slurry (e.g., abrasive pre-coatedparticles 520) and the material to be polished (e.g., film 510). Inaddition, because the pre-coated abrasive particles can be pre-coated by“polymer like” materials, the surface defectivity on the film beingpolished may be decreased.

Precursor Pre-Coating Embodiment

According to embodiments, a portion of the abrasive particles can bemanufactured having partial or complete pre-coatings of one or moreadditive precursors. Thus, the abrasive particle does not bond with anadditive, but instead is combined (e.g., coated) with a precursor ableto bind one or more additives to the abrasive particle. For instance,FIG. 6 is a cross-sectional illustration showing a pre-coated abrasiveparticle manufactured with an additive precursor coating which is inturn coated with an additive. As shown in FIG. 6, pre-coated abrasiveparticle 600 comprises an abrasive particle 610 coated partially orcompletely with precursor 620. Precursor 620 can in turn be coatedpartially or completely with one or more additives 630.

Interaction 640 between the abrasive particle and precursor coating mayinclude bonding, or attractions such as covalent and ionic bonding, andforce attractions such as Van der Waals force. Interaction 650 betweenthe precursor and additive(s) may also include bonding, or attractionssuch as covalent and ionic bonding, and force attractions such as Vander Waals force. For example, FIG. 7 is a cross-sectional illustrationshowing a pre-coated abrasive particle manufactured with a precursorparticle covalently bonded to it which is in turn covalently bonded toan additive particle. As shown in FIG. 7, pre-coated abrasive particle770 comprises abrasive particle 772 covalently bonded 780 to precursor774 which is in turn covalently bonded 782 to additive 776.

The slurry and additive particles, pre-coating methods, and pre-coatingsystems described above, also apply to pre-coating abrasives withprecursor(s) and resulting slurries thereof. Thus, during manufacture,all or a selected ratio of the abrasives can be partially or completelypre-coated with one or more types of precursors for inhibitors,surfactants, oxidizers, chelating agents, and/or liquid polymers, orsome combination or ratio of any or all the above. In addition, theparticles pre-coated with precursors can also be directly coated withadditives (e.g., additives directly bonded to the abrasive particle andnot to the precursor) in addition to the precursor(s) as desired.

While various embodiments of the invention have been described, thoseskilled in the art will recognize that the potential embodiments of theinvention are not limited to those embodiments described, but can bepracticed with modification and alteration within the spirit and scopeof the appended claims. The description is thus to be regarded asillustrative instead of limiting.

1. A method comprising: chemically-mechanically polishing a wafer with apolishing slurry, wherein the slurry comprises: a solution; and aselected ratio of coated abrasive particles as compared to abrasiveparticles not coated, wherein said coated abrasive particles comprise aselected number of a plurality of abrasive particles each coupled to atleast one additive.
 2. The method of claim 1, wherein said wafercomprises a film formed on a substrate.
 3. The method of claim 1,wherein said ratio is substantially predictable with respect to time sothat said particles can be successfully shipped and used in saidpolishing at another facility.
 4. The method of claim 1, wherein saidpolishing further comprises: placing said wafer in contact with apolishing pad; providing movement to said polishing pad; and depositingthe slurry onto said polishing pad.
 5. The method of claim 1, whereinthe selected ratio comprises a first plurality of abrasive particlescoated with a chemical mechanical polishing (CMP) additive duringmanufacturing of the selected ratio, a second plurality of abrasiveparticles not coated with a chemical mechanical polishing (CMP) additiveduring manufacturing of the ratio, and a ratio of the first plurality tothe second plurality selected during manufacturing of the ratio.
 6. Themethod of claim 1, wherein said slurry is stable enough to betransported, from a location where said slurry was mixed, to a secondlocation, and successfully used at least 30 minutes after mixing, forchemical-mechanical polishing at the second location.
 7. The method ofclaim 1, further comprising, prior to polishing: transporting the slurryfrom a location where said slurry was mixed, to a second location;waiting to use the slurry at the second location for at least 30minutes.
 8. A composition comprising: a plurality of manufacturedabrasive particles having an abrasive characteristic suitable for use ina wafer polishing process during manufacture of circuit devices, saidplurality of manufactured abrasive particles comprising; a first numberof pre-coated abrasive particles as compared to a second number ofabrasive particles not coated, wherein said coated abrasive particlescomprise a plurality of abrasive particles each coupled to at least afirst chemical mechanical polishing (CMP) additive and a differentsecond CMP additive, wherein neither the first CMP additive nor thesecond CMP additive is a precursor or a surfactant; and a solution forpolishing a surface.
 9. The composition of claim 8, wherein saidplurality of manufactured abrasive particles comprise particles of asize suitable for a polishing slurry.
 10. The composition of claim 8,wherein said first CMP and second CMP additives are selected from thegroup consisting of an inhibitor an oxidant, and a chelating agent. 11.The composition of claim 8, wherein the abrasive particles are selectedfrom the group consisting of silica, ceria, alumina, titanium oxide, anddiamond.
 12. The composition of claim 8, wherein the first, and secondnumbers are selectable with respect to time so that said slurry can betransported from a location where said slurry was mixed and the periodof time is at least 30 minutes.
 13. A system for producing pre-coatedabrasive particles for chemical-mechanical polishing, said systemcomprising: a means for pre-coating abrasive particles with additivesduring fabrication of the abrasive particles, wherein said pre-coatingabrasive particles comprises coating ones of a plurality of abrasiveparticles with at least one additive during manufacture of saidpre-coated abrasive particles.
 14. The system of claim 13 furthercomprising: a means for providing a selected ratio of pre-coatedabrasive particles as compared to the abrasive particles not pre-coatedby the additive.
 15. The system of claim 13, further comprising: a meansfor manufacturing a plurality abrasive particles by fuming or shearmixing; a means for mixing the coated abrasive particles with a solutionto form a polishing slurry.
 16. A method comprising: pre-coating aplurality of abrasive particles with chemical mechanical polishing (CMP)additive after manufacturing of the abrasive particles; and mixing thepre-coated abrasive particles with a solution to form a polishingslurry; then storing or transporting the slurry.
 17. The method of claim16, wherein coating comprises shear mixing to from particles of a sizesuitable for a polishing slurry to polish electronic devices on siliconsubstrate.
 18. The method of claim 16, wherein manufacturing comprisesone of fuming and shear mixing.
 19. The method of claim 16, whereincoating comprises introducing a plurality of additives to the pluralityof abrasive particles to form a plurality of coated abrasive particleshaving a coating including the plurality of additives.
 20. The method ofclaim 16, wherein the plurality of abrasive particles comprise particlesof approximately a first size and particles of approximately a secondsize to form first size coated particles having a coating including theplurality of additives, and a second size coated particles having acoating including the plurality of additives.